Developments in telecommunications technology have expanded the availability of information services to the home. For example, previously television and telephone services were each carried into the home by dedicated lines. However, it is now possible for telephone operators (telcos) to provide video content, and for cable operators to provide telephone service. Furthermore, the development of the Internet has enabled new alternatives for provision of information and service to the home. These advancements have brought about new competitive pressures. In particular, competition has driven requirements for quality-of-service (QOS) and Quality of Experience (QOE).
One aspect of QOS/QOE is fault tolerance. Should service be interrupted due to a component failure or other interruption in the transmission path, it is critical that service be restored with minimum or no disruption to the user. In the case of a video broadcast, the user should experience a minimum number of skipped, repeated or distorted video frames, as well as a minimum disruption in sound.
Broadcast video may be sourced from terrestrial broadcast feeds or satellite downlinks, and can be digitized and distributed via packet based networks as multiple “multicast streams.” These streams are delivered over a high-speed link, typically Gigabit Ethernet, to an edge or first hop router. The edge router advertises the multicast group(s) to the network. In conventional systems, such a router can detect overall link failures, e.g., loss of all multicast groups, loss of overall synchronization etc. When such failures occur, the edge router can control “failover,” e.g., switching or switchover to an available redundant path. However, conventional approaches cannot detect failures on individual multicast streams, and thus cannot make failover decisions on a stream basis. Thus, there is a possibility that individual stream failures can go undetected, and therefore unmitigated. This can result in substantial disruption to the viewer, with consequential negative implications to the service provider.
From the above, there is a need for a system and method to detect individual multicast stream failures in digital broadcast video systems, and to allow for rapid failover to a redundant source.